The objectives of this proposed research are to: 1. Determine the effect of open-bite malocclusion on oral port constriction during speech. 2. Evaluate the relationship between degree of openbite, area of oral port and sound intelligibility. 3. Determine whether variations in area of the oral port result in observable variations in the acoustic speech wave and if so, do these variations in the acoustic speech wave relate to listener judgments of intelligibility. 4. Identify the effects of overjet in the presence of openbite on area of the oral port and sound intelligibility. 5. Determine whether the high frequency of fricative distortions in the cleft population is related to size of the oralport constriction or presence of malocclusion and anterior spacings. 6. Determine the effect of overbite on oral port constriction and sound production in cleft palate and non-cleft subjects. The methods to be utilized to study these relatonships between anterior malocclusion and speech performance will include: 1. the pessure-flow technique for measuring oral port opening and velopharyngeal orifice size. 2. Acoustic analysis. 3. Subjective speech judgments. 4. Measurements from study models.